js实现考试时间倒计时

             daojishi();     }

      var counttime=90*60;//总秒钟           function daojishi(){      if(counttime>=0){             var ms = counttime%60;//余数 89%60==29秒             var mis = Math.floor(counttime/60);//分钟             if(mis>=60){              var hour=Math.floor(mis/60);

     mis=Math.floor((counttime-hour*60*60)/60);

              document.getElementById("mss").value=hour+"小时"+mis+"分"+ms+"秒数";             }else if(mis>=1){              document.getElementById("mss").value=mis+"分"+ms+"秒数";              }else{              document.getElementById("mss").value=ms+"秒数";              }

                 counttime--;              vartt =  window.setTimeout("daojishi()",1000);   }else{       window.clearTimeout(vartt);       window.confirm("考试时间结束,请单击提交");        tijiao();         }

        }          function tijiao(){        document.forms[0].submit();     }//-->